There is a heretofore known chair-type massage apparatus that has mounted in its backrest a massage mechanism in which a pair of right-hand and left-hand massage members are operated to provide a massage action. This massage mechanism is required to move so as to conform to the spine of a user sitting on a seat of the apparatus, and is therefore provided with a vertical movement mechanism. The massage mechanism and the vertical movement mechanism constitute a back kneading device. As a back kneading device of this type, there has been proposed a device equipped with an advancing and retracting mechanism capable of causing a massage member to protrude forward beyond a normal massage position, as well as to return it to the original normal position (refer to Patent Literature 1, for example).
In this advancing and retracting mechanism, a base member, which is moved up and down in the backrest by the vertical movement mechanism, is provided independently of the massage mechanism. The massage mechanism is supported on this base member in such a manner that the upper end of the massage mechanism can be rocked back and forth about a lower pivot shaft. Moreover, over the base member, there is disposed a slider which is raised and lowered by a feed screw mechanism having a longitudinally pointing axis. The slider and the upper end of the massage mechanism are coupled to each other by a transmission arm.
That is, as the slider placed over the base member is raised, the upper end of the massage mechanism is pushed forward via the transmission arm, whereupon the massage mechanism is rocked, at its upper end, forward about the lower pivot shaft as a pivotal point. In this way, the right-hand and left-hand massage members are caused to protrude forward.